Process for producing components by powder injection molding

Patent metadata

Field	Value
Publication number	US-9403212-B2
Application number	US-201213472915-A
Country	US
Kind code	B2
Filing date	May 16, 2012
Priority date	May 18, 2011
Publication date	Aug 2, 2016
Grant date	Aug 2, 2016

Abstract

Process for producing a shaped metallic body from a thermoplastic composition by injection molding or extrusion to form a shaped part, removal of the binder and sintering, wherein a thermoplastic composition composed of a metal powder and a polymer mixture B 1 ) and B 2 ) based on a polyoxymethylene homopolymer or copolymer B 1 ) is used as binder and to remove the binder
a) the shaped part is treated with a solvent which extracts the binder component B 2 ) from the shaped part and in which the binder component B 1 ) is insoluble, b) the solvent is then removed from the shaped part by drying and c) the shaped part is treated thermally at from 140 to 200° C. in an oxygen-comprising atmosphere, as a result of which the binder component B 1 ) is removed from the shaped part;

and also a shaped metallic body which can be obtained in this way.

First claim

The invention claimed is:

1. A process for producing a shaped metallic body which comprises injection molding or extruding a thermoplastic composition to form a shaped part, removal of the binder and sintering, wherein a thermoplastic composition comprising
A) from 40 to 65% by volume of at least one sinterable metal powder A,
B) from 35 to 60% by volume of a binder mixture consisting of
B 1 ) from 50 to 95% by weight of one or more polyoxymethylene homopolymers or copolymers;
B 2 ) from 5 to 50% by weight of a polymer selected from among aliphatic polyurethanes, aliphatic uncrosslinked polyepoxides, polyethers, aliphatic polyamides, polyacrylates and mixtures thereof which is homogeneously dissolved or dispersed with an average particle size of less than 1 μm in B 1 ) and

C) from 0 to 5% by volume of a dispersant,
where the sum of the components A), B) and C) does not exceed 100% by volume, is used;
and to remove the binder
a) the shaped part is treated with a solvent which extracts the binder components B 2 ) and optionally C) from the shaped part and in which the binder component B 1 ) is insoluble,
b) the solvent is then removed from the shaped part by drying and
c) the shaped part is treated thermally at 140-200° C. in an oxygen-comprising atmosphere, as a result of which the binder component B 1 ) is removed to an extent of at least 20% by weight from the shaped part.

2. The process according to claim 1 , wherein the proportion of the binder component B 2 ) is from 15 to 35% by weight.

3. The process according to claim 2 , wherein the binder component B 2 ) is a polyether selected from the group consisting of polyethylene oxide, polypropylene oxide, poly-1,3-dioxepane, poly-1,3-dioxane, poly-1,3-dioxolane, polytetrahydrofuran (poly(tetramethylene) oxide) and mixtures thereof.

4. The process according to claim 3 , wherein step a) is carried out at a temperature above room temperature up to the boiling point of the solvent.

5. The process according to claim 4 , wherein the treatment with a solvent in step a) is carried out until the binder component B 2 ) has been removed to an extent of at least 75% by weight from the shaped part.

6. The process according to claim 5 , wherein the thermal treatment in step c) is carried out in a convection oven.

7. The process according to claim 6 , wherein the thermal treatment in step c) is carried out at 140-170° C.

8. The process according to claim 7 , wherein the thermal treatment in step c) is carried out until the binder component B 1 ) has been removed to an extent of at least 85% by weight from the shaped part and the treatment with a solvent in step a) is carried out until the binder component B 2 ) has been removed to an extent of at least 85% by weight from the shaped part.

9. The process according to claim 1 , wherein the binder component B 2 ) is a polyether selected from the group consisting of polyethylene oxide, polypropylene oxide, poly-1,3-dioxepane, poly-1,3-dioxane, poly-1,3-dioxolane, polytetrahydrofuran (poly(tetramethylene) oxide) and mixtures thereof.

10. The process according to claim 1 , wherein step a) is carried out at a temperature above room temperature up to the boiling point of the solvent.

11. The process according to claim 1 , wherein the treatment with a solvent in step a) is carried out until the binder component B 2 ) has been removed to an extent of at least 75% by weight from the shaped part.

12. The process according to claim 1 , wherein the thermal treatment in step c) is carried out in a convection oven.

13. The process according to claim 1 , wherein the thermal treatment in step c) is carried out at 140-170° C.

14. The process according to claim 1 , wherein the thermal treatment in step c) is carried out until the binder component B 1 ) has been removed to an extent of at least 50% by weight from the shaped part.

15. The process according to claim 1 , wherein the thermal treatment in step c) is carried out until the binder component B 1 ) has been removed to an extent of at least 85% by weight from the shaped part.

16. The process according to claim 1 , wherein the treatment with a solvent in step a) is carried out until the binder component B 2 ) has been removed to an extent of at least 85% by weight from the shaped part.

17. The process according to claim 1 , wherein the thermoplastic composition consists of components A), B), and C).

Assignees

• Ter Maat Johan
• Blömacher Martin
• Wohlfromm Hans
• Basf Se

Inventors

• Ter Maat Johan
• Blömacher Martin
• Wohlfromm Hans

Classifications

• B22F3/225

  by injection molding · CPC title

• B22F3/1021 Primary

  Removal of binder or filler (removal of binder from ceramics C04B35/638) · CPC title